ABSTRACT
In a laser diode, smaller thickness of the region of excess carrier concentration is necessary because of lower pumping current requirement. But there is limit to the minimum thickness possible in a homojunction diode. However, a double heterojunction diode provides this opportunity. It allows effective thickness reduction to values below 10 nm. A quantum well laser utilizes quantum mechanical phenomena to achieve enhanced performance. Quantum wells also form the core elements of LEDs. The thickness of the barrier layer, its doping, the number of wells, and the use of a graded InN composition in a GaN LED are valuable inputs to the design of a good LED for a specific application. Another device benefitting from quantum wells is the solar cell. Multiple quantum well solar cells can cater to the broad energy range of the solar spectrum, thereby increasing the efficiency.
